Surgery / Benign cystic lesion of the oral cavity

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Benign cystic lesion of the oral cavity

Cyst is a pathologic cavity within hard or soft tissue, lined by epithelium and contain fluid, semifluid or gas and surrounded by connective tissue wall or capsule. Whatever the precipitating factor for the initiation of the cystic lesion, it is followed by cyst formation due to proliferation of the epithelial lining and fluid accumulation within the cyst cavity. The cyst continues to enlarge due to increase in the volume of the contents and resorption of the surrounding bone that might cause displacement of the adjacent vital structures.

Classification of cyst

I. Intraosseous cysts

1. Epithelial Cysts:

A.Odontogenic epithelial origin

i.Developmental

a.Primordial cyst (keratocyst)

b.Dentigerous (follicular) cyst

c.Lateral periodontal cyst

d.Calcifying odontogenic cyst

ii.Inflammatory

a.Radicular cyst (apical)

b.Residual cyst

B.Nonodontogenic epithelial origin (Fissural cyst):

i.Median mandibular

ii.Median palatal

iii.Globulomaxillary

iv.Incisive canal (nasopalatine duct cyst)

2.Nonepithelial cysts:

A.Solitary bone cyst (traumatic)

B.Aneurysmal bone cyst

C.Stafne’s bone cavity

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II. Soft tissue cysts

1.Odontogenic:

Gingival cysts (Adult and Infant)

2.Nonodontogenic (fissural):

A.Anterior median lingual cyst

B.Nasolabial cyst

3.Retention cysts:

Salivary gland cysts (Mucocele and Ranula)

4.Developmental/congenital cysts:

A.Dermoid and epidermoid cysts

B.Branchial cyst (cervical/intraoral)

C.Thyroglossal duct cyst

D.Cystic hygroma

Primordial Cyst (Keratocyst)

Primordial cyst is a developmental anomaly, which arises from odontogenic epithelium, the main sources being: Dental lamina or its remnants, enamel organ (by degeneration of the stellate reticulum) prior to the formation of calcified structures, thus, this cyst is found in place of a tooth (from the normal series or supernumerary). Incidence: It is about 5 to 10% of odontogenic cysts of the jaws, more in the second to fourth decades of life with males’ predilection.

Site: Mostly affect the mandible, involve the angle, the ascending ramus and body of the mandible, however, it can occur anywhere in the jaws.

Clinical features: It is symptomless until the cysts have reached a large size. This is because the primordial cyst initially tends to grow in an anteroposterior direction within the medullary cavity and clinically observable expansion of the bone occurs late. The enlarging cyst may lead to displacement of the teeth, percussion of the teeth overlying the cyst may produce a dull sound. A single missing tooth from the normal series, and the teeth adjoining the cyst are vital. Large infected mandibular cysts result in labial paresthesia or anesthesia.

Radiological features: unilocular or multilocular radiolucency

Cyst contents (aspirate): contain cheesy like material, viscoid suspension of keratin.

Recurrence: Keratocyst have a pronounced tendency to recur. The recurrence rate may vary from 5-60% with most occurring in the first 5 years. Some of the possible reasons reported for recurrence are as follows: Presence of satellite or daughter cysts, cystic lining is very thin and fragile, portions of which may be left behind after enucleation, epithelial lining of keratocysts have an infiltrative growth potential.

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Patients with nevoid basal cell carcinoma syndrome, have a particular tendency to form multiple keratocysts (Gorlin-Goltz syndrome).

Treatment

Treatment should always be based on proper clinical assessment. Marsupialization is incorrect for the treatment of keratocysts, owing to their high tendency to recur. Bramly (1971-1974) outlined the surgical management of odontogenic keratocyst as follows:

•Small single cysts with regular spherical outline:

Enucleated from an intraoral approach, provided the access is good.

•Larger or less accessible cysts with regular spherical outline: Enucleated from an extraoral approach.

•Unilocular lesions with scalloped or small multilocular lesions:

Marginal resection. The defect is closed primarily, left to heal by secondary intention or can be filled with bone graft.

•Large multilocular lesions with or without cortical perforation:

En bloc segmental resection of the involved bone followed by a reconstruction plates and bone grafting.

Carnoy's solution or 5-fluorouracil can used as conservative approach for large keratocysts to reduce recurrence.

The patient should be reviewed regularly over a long follow-up.

Dentigerous (Follicular) Cyst

Dentigerous cyst developed as a result of enlargement of the follicular space of the whole or part of the crown of an impacted tooth and is attached to the neck of the tooth.

Incidence: More common than keratocyst but less common than the inflammatory types. The common age affected are the first to third decades. Incidence is slightly more in males.

Site: It occurs more frequently in the mandible than the maxilla. The most frequent teeth involved in descending order are the lower third molars, upper canines, upper third molars and the lower premolar teeth.

Clinical features: Dentigerous cysts have the potential, to attain a large size, results in facial asymmetry. Pain may be a presenting symptom, if secondary infection present. Missing a tooth from the normal series, unless the cause is a supernumerary tooth. Adjacent teeth may be tilted. Later as the cyst expands the cortical bone becomes thinned. This fragile outer shell of bone gives sound described as egg-shell crackling.

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Radiological features: Radiographs will generally reveal a unilocular radiolucency associated with crowns of impacted tooth; at times a multilocular radiolucency can be seen when the cyst is of irregular shape due to bony trabeculations. Cysts have a well-defined sclerotic margin unless when they are infected then the margins are poorly defined. As compared to the other jaw cysts, dentigerous cysts have a higher tendency to cause root resorption of adjacent teeth. Radiolucency around the impacted tooth presents in three variations (circumferential, lateral or coronal).

Cystic contents: Consist of clear yellowish fluid, in which cholesterol crystals may be present, or purulent material, if infection has occurred.

Treatment: Treatment via an intraoral or extraoral approach. Treatment is decided according to the size of the cyst, adequate access and whether it is desirable to save the involved tooth:

•Marsupialization: If the cyst is very large in size and the involved tooth/teeth are to be maintained. The tooth may erupt into occlusion as the defect heals with normal bone.

•Enucleation: the cyst can be enucleated together with the involved tooth when the

cyst is small and its removal not damage adjacent vital structures. Prognosis: Recurrence is a possibility if some epithelium remains.

Lateral Periodontal Cysts

Lateral periodontal cysts are rarely occurring, found lateral to the roots of vital teeth, and mostly found in adults.

Site: It occurs more often in the mandible. Mostly affect mandibular canines, premolars and third molar roots, followed by the anterior region of the maxilla. Clinical features: Mainly symptomless, and are discovered accidentally on radiographs. A gingival swelling may occur on the buccal or lingual aspect, and this must be differentiated from a gingival cyst.

Radiological features: Radiographs reveal a well-defined round or ovoid radiolucency with a sclerotic margin, the lamina dura of the involved tooth is destroyed. Most of the cysts are smaller than 1 cm in size and are seen to be present between the cervical margin and apex of the root and in the bifurcation of lower third molar roots.

Cystic contents (aspirate): It has a serous cheesy content. Treatment: Enucleation is the method of choice.

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Calcifying epithelial odontogenic cyst

The calcifying odontogenic cyst, also called odontogenic ghost cell cyst or Gorlin cyst. It has many features of tumors so it is placed in the category of tumors in the latest WHO classification as Calcifying cystic odontogenic tumor.

Incidence: It occurs more commonly in children and young adults.

Site: Most common site of occurrence is in the anterior part of both jaws.

Clinical features: Mainly symptomless, and discovered accidentally on radiographic examination. Swelling is the most frequent complaint, rarely there is pain. A peripheral or intraosseous lesion may be seen, the latter produce a hard bony expansion, in a few cases displacement of the teeth may be seen.

Radiological features: Cyst will be seen between the roots of the teeth and might reveals resorption of the roots of the adjacent teeth. The periphery may be well demarcated or irregular, it is either unilocular or multilocular in pattern.

Cortical perforation may be evident and calcifications may be seen within the bone cavity. The cyst may be associated with a complex odontome or impacted tooth. Treatment: Surgical excision of the intraosseous cyst.

Radicular Cysts

The radicular cyst is an inflammatory cyst which results due to infection extending from the necrotic pulp into surrounding periapical tissues. It may develop apically and termed as a periapical radicular cyst, or on the side of the root and termed as a lateral radicular cyst, this cyst should be differentiated from a developmental lateral periodontal cyst which is associated with a vital tooth.

Incidence: This is the most common cysts of odontogenic origin, males more affected and the peak incidence is in the second and third decades.

Site: The incidence is highest in the anterior maxillary and the posterior mandibular teeth.

Clinical features: It is symptomless and may be discovered by radiographical examination. The involved tooth is nonvital and slowly enlarging swellings. Pain may be a significant in the presence of suppuration. In the maxilla, buccal and palatal or only palatal expansion might be noted in lateral incisor or a palatal root of molars. An intraoral sinus tract may be identified with discharging pus when the cyst is infected.

Radiological features: A round or ovoid shaped radiolucency, generally outlined by a narrow radio-opaque margin that extends from the lamina dura of the involved tooth/teeth.

Cystic contents (Aspirate): A straw colored or brownish fluid and cholesterol crystals. In case of infection pus may be present.

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Treatment: Nonvital teeth that are associated with the cyst, can either be extracted, preserved by endodontic treatment or apicoectomy. External sinus tracts should always be excised to prevent epithelial ingrowth. The commonly employed surgical procedure for radicular cysts is enucleation, with primary closure. Small cyst can be removed through the socket after extraction of the affected tooth.

Residual Cyst

It occurs when incompletely enucleated periapical granuloma or cyst, that potentially enlarges after extraction of nonvital tooth which is associated with periapical lesion.

Incidence: It is identified mainly in elderly patients with no sex predilection.

Site: The incidence is greater in the maxilla than in the mandible. It is typically seen in edentulous sites.

Clinical features: Majority of the cases are asymptomatic and are discovered on radiographic examination.

Treatment: Enucleation

Median palatal cyst

Arises as a result of epithelial inclusion or entrapments during the fusion of the palatine processes of the maxilla.

Incidence: It is a rare cyst mainly affect adults with no sex predilection.

Site: It is seen in the hard palate, between the incisive fossa and the posterior border of the hard palate.

Clinical features: No complaint unless the cyst becomes large, with expansion of bone and a palpable ovoid swelling in the mid-palatal region.

Radiological features: A maxillary occlusal view will help to identify the ovoid, or irregular radiolucency in the mid-palatal region, often it is difficult to distinguish the cyst from an extensive incisive canal cyst.

Treatment: Enucleation with primary closure.

Globulomaxillary Cyst

It arises from epithelium inclusions at the site of fusion of the globular process of the medial (frontonasal) process and the maxillary process.

Incidence: It is uncommon, appear at adult life.

Site: It is seen between the maxillary lateral incisor and canine teeth.

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Clinical features: The maxillary lateral and canine teeth are tilted coronally with root divergence and associated with vital teeth.

Radiological features: If the cyst is small, it is spherical in shape, as it enlarges a typical pear-shaped radiolucency between the maxillary lateral incisor and canine. The roots reveal divergence and the lamina dura of both teeth is intact.

Treatment: Enucleation and primary closure.

Nasopalatine Duct Cyst (Incisive canal cyst)

It arises from epithelial remnants within the nasopalatine canal, which connects the oral and nasal cavities in the embryonic stage.

Incidence: More in male, mostly seen in fourth to sixth decades.

Site: The cyst may arise at any point along the incisive canal, between the apices of the maxillary central incisors. Cyst of the palatine papilla, is another variant which is located solely within the soft tissues in the region of the incisive papilla, at the opening of the canal.

Clinical features: Majority is asymptomatic, it does not attain a very large size, beyond 1.5 to 2 cm. The common symptom is a recurrent swelling, on the labial aspect between the central incisors. Displacement of the teeth is common, the patients complain of swelling, pain and a 'salty taste'. Burning sensations or numbness may present, which is due to pressure exerted by the cyst on the nasopalatine nerves. The central incisors are vital.

Radiological features: The nasopalatine duct cyst is seen as a well-defined cystic outline, between or above the roots of the maxillary central incisor teeth. It can be round or ovoid, some may appear as heart-shaped. Kay (1972) reported that any radiograph of the fossa which showed a shadow less than 6 mm wide may be considered within normal limits as incisive canal fossa in the absence of specific symptoms. The roots of the central incisors may show divergence and an intact lamina dura around the tooth apices.

Cystic contents (Aspirate): Aspiration reveals viscous mucoid fluid or even pus if the cyst has been infected.

Treatment: Enucleation, by raising a palatal flap from canine to canine.

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Solitary bone cyst

It is also termed as traumatic or hemorrhagic bone cyst.

Etiology: Mainly due to trauma and hemorrhage with failure of organization. Incidence: It is uncommon lesion, occurs particularly in children and adolescents, males are more affected.

Site: Often seen in the long bones. It is rarely seen in the maxilla. The majority are seen in the subapical region, above the inferior alveolar canal, in the cuspid and molar region.

Clinical features: Usually symptomless and detected incidentally during a radiographic examination. The cortex is usually thinned but expansion occurs later on and may first involve the lingual aspect below the mylohyoid ridge and the associated teeth are vital.

Radiological features: The cyst appears as a unilocular cavity, with a characteristically scalloped outline to the border around the roots of the teeth. In the anterior region, the outline is usually regular and general shape is round or oval, with no indentations. The roots of related teeth may be displaced, lamina dura is intact.

Cystic contents (Aspirate): A deep yellow colored fluid or fresh blood may be obtained. Some cysts may be reported empty. It is suggested that they may contain gas such as nitrogen, oxygen and carbon dioxide.

Treatment: Surgical exploration is required for diagnosis and treatment. Gentle curettage stimulates hemorrhage which results in rapid obliteration of the defect and eventual healing by new bone formation.

Aneurysmal Bone Cyst

Often seen in the long bones and spine, it is rarely seen in the jaws.

Etiology: Mainly due to trauma, possible relationship with the giant cell lesion, or variation in the hemodynamics of the area.

Incidence: It is rare, there is no specific sex predilection. It is seen mainly in children, adolescents or young adults.

Site: More commonly seen in the posterior region of the mandible.

Clinical features: Firm swellings, rapid enlargement, and displacement of the teeth which are vital. Egg-shell crackling may be exhibited.

Radiological features: The lesions are usually unilocular, oval or spherical in shape, causing considerable ballooning of the cortex. At times internal ridges or incomplete septae may give a multilocular appearance described as honey-comb or soap-bubble appearance. Teeth may be displaced and root resorption. The outer cortical plate may be destroyed.

Cystic contents (Aspirate): Dark venous blood can be aspirated.

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Treatment: Curettage is the choice of treatment, though, incomplete removal in large lesions is liable to result in recurrence.

Local excision with bone grafting has been suggested in very large lesions. Radiotherapy is contraindicated as it may result in the occurrence of post radiation sarcoma.

Stafne's Bone Cavity

Although, Stafne's bone cavity is not a cyst, it is included because of their clinical similarity to cysts of the jaw bones and the frequent difficulty in differential diagnosis.

Etiology: Stafne cavities may be due to failure of the normal deposition of bone during development of the jaws in an area formerly occupied by cartilage, or by a lobe of normal submandibular salivary gland.

Incidence: Relatively uncommon, the majority have been reported in males over 40 years of age.

Site: Below the inferior alveolar canal, mainly unilateral.

Clinical features: These are symptomless lesions discovered during routine radiological examination, the lesions are non-progressive.

Radiological features: The depression is rounded or oval, 1-3 cm in size, below the inferior alveolar canal, posterior to the mandibular first molar.

Cystic contents (Aspirate): Empty cavity will yield air

Treatment: No surgical intervention is required. Regular radiological follow-up is advised, as they constitute an area of weakness and pathologic fracture may occur.

Gingival Cysts

The only specific criterion for these lesions is its location in the gingival tissues. There are two types of gingival cysts:

Gingival Cyst of the Adult

Etiology: Arise from remnants of the dental lamina.

Incidence: It is relatively rare and has no sex predilection. It is known to occur in adults in the fifth or sixth decades.

Site: Occurs more frequently in the mandible than in the maxilla. They appear particularly in the canine and premolar region of the mandible.

Clinical features: The cysts are seen in the attached gingiva or the interdental papilla on the labial aspect. The lesions are painless, slow-growing swellings that have a smooth surface, may be of normal color or bluish. They are soft and fluctuant and the adjacent teeth are vital.

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Treatment: Surgical excision is curative and there is no tendency for recurrence.

Gingival Cyst of Infants

Gingival cysts of infants are frequently referred to as Bohn's nodules or Epstein's pearls.

Etiology: The cysts arise from epithelial remnants of the dental lamina. Incidence: Mainly seen in newborn infants, rarely seen after 3 months of age. Site: Bohn's nodules are found on the buccal or lingual aspects of the dental ridges, whereas Epstein's pearls are seen along the mid-palatine raphe.

Clinical features: They appear as discrete white swellings. They may be single or multiple and clinically resemble a mucocele.

Treatment: No treatment is required as they rupture spontaneously on eruption of the underlying teeth.

Nasolabial Cyst

Nasolabial cyst is a true soft tissue fissural cyst that does not occur within bone. Incidence: Uncommon lesions, mainly seen in the third to fifth decades of life and predominantly affects female.

Site: They are seen above the buccal sulcus under the ala of the nose, at the junction of the lateral nasal and the maxillary processes.

Clinical features: Majority of the cases are unilateral, the swelling is seen involving the lip, that lifts up the nasolabial fold and obliterates the labial sulcus. The cysts are fluctuant and painless unless infected secondarily.

Cystic contents: The cyst contains straw-colored or whitish mucinous fluid. Treatment: The cyst should be enucleated surgically by an intraoral approach. Care should be taken while separating the cystic lining from the nasal mucosa.

Retention (Salivary Glands) Cysts Mucocele

Two types of distinct entities described are, the true retention cyst which is lined by epithelium and the other is the mucous extravasation cyst which occurs because of the pooling of mucus, it does not have any epithelial lining and is surrounded by connective tissue.

Etiology: Mainly due to either obstruction of a salivary duct or trauma.

Incidence: Affect the minor salivary gland, no age or sex predilection. However, retention cysts occurred more frequently in older patients, whereas the extravasation cysts occur more commonly in the younger age group.

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